1. Field of the Invention
The present invention relates to a picking system and a picking method used for managing articles in a physical distribution route.
2. Description of the Related Art
In an article delivery system, labels having barcodes printed on them, for example, are attached to articles. A computer manages various delivery conditions of articles based on identification information read from the barcodes.
For example, WO2006/059676 discloses an automated warehouse equipped with a picking system arranged to manage articles having an IC tag attached. The picking system has a picking robot arranged to extract articles from a carrier or the like one at a time and place them in a predetermined position. A hand of the picking robot is installed with an ID reader for reading data from an IC tag attached to an article. Each time the hand places an article, the ID reader reads the ID of the article. As a result, a computer can accurately recognize the IDs and positional relationships of the articles placed by the hand.
A problem occurring with a conventional picking system will now be explained. After the articles are placed, the computer can accurately manage the articles based on the positions and ID information. However, if an article other than a scheduled article is placed in a particular position, the computer will not recognize that an incorrect article is in that position. Consequently, a user cannot easily learn about the incorrect article placement.